Underbalanced drilling is a process used on gas wells where the internal pressure in the hole or wellbore is at a lower pressure than that of the fluid pressure in the formation being drilled. This results in formation fluid flowing into the wellbore and up to the surface as the hole is being drilled. To assist in this operation, inert gas, such as nitrogen gas, is injected into the drilling mud to reduce its density and thus its hydrostatic force throughout the well depth. The process of controlling such an operation is fraught with dangers such as high pressures and working at elevated locations, and it consumes much time when done properly and safely.
The current method of releasing the gas pressure involves having a worker stationed on the drilling rig floor manually attach a hose attached to a string float for bleeding of the gas. The hose is subject to freezing in cold weather. The task of attaching the hose is potentially dangerous as the worker is required to stand on a ladder to access the float valve. What is needed is a safer way of releasing gas pressure from a drill string.